Two-stage filter in single housing



March 13, 1951 c, D. NUGENT' 2,545,374

TWO-STAGE FILTER IN SINGLE HOUSING Filed Aug. 11, 1949 2 Sheets-Sheet 1Jfiveniar C OTZZJSS D. we?! March 13, 1951 c. D. NUGENT 2,545,374

TWO-STAGE FILTER IN SINGLE HOUSING Filed Aug. 11, 1949 2 Sheets-Sheet 2lwverziar- C OYZLSS Z). M @118 Patented Mar. 13, 1 951 'IWG-STAGE FILTERIN SINGLE HOUSING Corliss ll). Nugent, Winnetka, Ill., assignor to Win.

W. Nugent & (30., 1110., Chicago, 111., a corporation of IllinoisApplication August 11, 1949, Serial No. 109,745

More particularly, the invention relates to twostage filters having aplurality of removable filter elements for both coarse and finefiltering, mounted on a single filter casing.

The principal object of the present invention is to provide an improvedfilter consisting of a single casing containing a plurality of removablefilter units arranged in series, for filtering both coarse and fineliquid, with bypass means in the finer filtering units, to permit thebypassing of liquid around the latter under conditions where the flow offluid through the coarse filtering unit may overtax the capacity of oneor more of the fine filtering units in the series therewith.

Other objects of the invention will appear from the followingdescription.

The invention may best be understood by reference to the accompanyingdrawings, in which:

Figure .1 is a plan View of a filter casing constructed in accordancewith my invention;

Figure 2 is a sectional view, taken on line 2-2 of Figure 1, with thecentral portion of the filter casing broken away. 4

Referring now to details of the embodiment of 4 Claims. (Cl. 210184) myinvention shown in the drawings, a single having a plurality ofperipheral lugs I1, slotted' outwardly for receiving bolts I8 pivotallymounted on a ring is surrounding the upper edge of the casing. When inclosed position, the cover [5 seals the main filtering compartment 29within the casing I0.

At the bottom of the casing is an inlet 2! and an outlet 22. The inletcommunicates with an interior compartment 23 partially defined by abottom wall 24 and, in turn, communicating with a filtering compartment20 through an aperture 25 in the partition H. An upstanding nipple 2B isfixed in the aperture 25, said nipple being' adapted for receiving oneof the filtering elements in seated position thereon, as will presentlyappear. The outlet 22 communicates with an interior compartment 21,partially defined by a bottom wall 24a, below the transverse parti tionII and, in turn, communicates witha plurality of apertures 28 and 29 insaid bottom partition. Upstanding nipples 30 and 3| may be similar tothe nipple 26 previously mentioned as communicating with the inlet 2!and are also adapted for receiving detachable filter units in seatedengagement therewith, as will presently appear.

It will now be understood from the above description that the inletcommunicates with one upstanding inlet nipple leading into the mainfiltering compartment 20, while the two upstanding nipples 3t and 3|afford communication from the main filtering compartment 2c to theoutlet 22.

Referring now to the filtering units which are detachably mounted withinthe main filtering compartment 29, a relatively coarse filtering unit,indicated generally at 35, is detachably connected at its inlet and tothe single inlet nipple 26, while two other filtering units 35 and 31,both defined for much finer filtering action than the coarse filter unit35, are detachably connected at their outlet ends to the outlet nipples36 and 3| respectively.

In the form of coarse filter unit 35 shown here-' in, I have shown forillustrative purposes a so called bag-type filter unit of the'kind whichhas gone into extensive use in single filters for relatively coarsefiltering and is broadly disclosed in prior Patents No. 1,909,308 andNo. 1,918,980. Since these bag-type filter units are well known in theart, detailed description should not be necessary, excepting to pointout the main elements of the bag-type filter unit as follows:

The filter unit 35 is built around a central tubular member 40, to whichis connected as by threaded lugs 4| 4| a plurality of fiat fabric bags42 which are wound spirally around the central tubular member 40. Thecentral tubular member 40 has one or more outlets 43 communicating withthe open ends of the several bags, so that the liquid to be filterednormally flows from the central tubular member outwardly through thefabric walls of the latter in the usual manner. The bags are usuallyenclosed in an outer mesh cover 46 of fabric or wire so that thefiltering unit is maintained in generally cylindrical form.

The filtering unit 35 also has a built-in bypass valve, hereinconsisting of a ball 4? urged by a coil spring 48 against a restrictedseat 49 near the upper end of the tubular member at. The extreme upperend of the tubular member 42 is closed as by a handle 50, having adepending hollow boss 5: threaded into the upper end of the tubularmember and forming an abutment for the upper end of the coil spring '48.Liquid by passed through the ball valve 4'! escapes through apertures52, 52 disposed above the bags 42 so that in the present form ofapparatus any bypassed liquid enters directly into the main filteringcompartment 20.

An upstanding stud 53 is axially disposed on the upper face of thehandle 50 and extends through an aperture 5.4 in a pressure plate 55,which holds all the filter units in place, as will presently appear.

The fine filter units 36 and 31 are both of the same construction,designed to give much finer filtering effect to the liquid bypassedtherethrough. In the form shown herein, each of the fine filter units isof the kind which has gone into extensive use in single filters and isbroadly disclosed in my prior Patent No. 2,352,732. Such fine filterunits are usually packed with relatively dense filtering materialdesigned to have a much finer filtering action upon liquid passingtherethrough than is the case with the bagtype filter hereinabovedescribed. Since these relatively fine filter units are also well knownin the art, detailed description should not be necesry, exceptin topoint the :main elemen f the units as follows:

The fine filtering units are each built around a central tubular memberell extending axially thereof and having a plurality of apertures 8 6|therea-long communicating with an outwardly flanged straining sleeve 62surrounding the cen-- tral portion of the. tube 52.. Flanged upper andlower end plates 63 and 64 are connected at op.- posite ends of the tube60 and a perforate container, herein consisting of a cylindrical wirescreen -65, has its upper and lower ends fitted in the flanged endplates 83, B4 to form a cylindrical compartment filled with suitablefilter.- ing material 66, a

Each of the filtering units 3.5 and 3'! has a bypass valve, hereinconsisting of a ball 67 urged by a coil spring 6.8 upwardly against arestricted seat 69 formed by a thimble l threaded into the upper end ofthe tube 68. The lower end of the coil spring 68 abuts against a disc ,Hwhich engages a reduced shoulder 12 in the tube 60. The thimble 15 isclosed at its upper end but is provided with one or more apertures M inthe side wall thereof above the end of the tube 69, so as to providecommunication between the interir of the main filtering chamber 25 andthe bypass ball valve 67.

An upstanding stud 16 is formed integrally with the top .of the thimble'50 and extends through an aperture ll in .the pressure plate 55 to forma centering member substantially simi.- lar to the stud 53 of thecoarser filtering unit 35.

The length of the coarse filtering unit 3.5, in-

cluding its central tubular member 4a and its top handle is the same asthe length of the two finer filtering units 36 and 31", with theircentral tubes .60 and their top thimbles Ill, .so that the pressureplate 5.5- is adapted to fit fiatwise over all three of the filteringunits 35, 36 and 3! and hold them by compression of a single centrallydisposed spring [9 abutting against the under face of the cap l5 so asto urge the lower ends of their central tubes in seated rel tion againsttheir respective nipples 2,5, 3.0 and 3! on the lower partition I I.

The use and operation of the apparatus I have been describing are asfollows;

Liquid entering the inlet .21 is led upwardly through the central tubefill of coarse filtering unit 3.5 and thence through the severalfiltering sity of replacing overclogged filter units may be 4 bags 42,outwardly into the main filtering chamher 29 of casing Ill. From thefiltering chamber 20 the-liquid will normally be passed in a dividedstream through the filtering media of the two fine filtering units 35and 37 into the two tubular members 60 of said last-named filteringunits, and thence downwardly to the outlet 22 of the casmg.

it will be understood that the capacity of a coarse filter unit 35, suchas the bag type herein disclosed is usually greatly in excess of thefiner filter units ,36 and 37. Therefore, in the form of apparatus shownherein, at least two of the finer filter units are required to take careof the liquid filtered through the coarse unit 35. In fact, underordinary conditions, finer filtering units of the kind contemplatedusually have less than one-half the capacity of a single coarsefiltering unit, even when the filtering units are new. Consequently, theself-contained bypass valves 5] in each of the fine filtering units 36and 31 are provided to take care or excessive pressure which maybe builtup within the main filtering compartment 28 from time to time during theuse of the filtering apparatus.

Moreover, it will be understood that the finer filtering units 3:5 and3? have a greater tendency to collect sediment and become clogged duringcontinued use than the bag type element filtering unit 35. Thebypassvalves 6'! in the fine filtering units, therefore, become Of increasingimportance during extended use of the apparatus, in order to insurecontinued flow through the system of oil, when one or more of the finerr filtering uni-ts may be bypassed during times of excessive pressurethereon, or even become fully inoperative due to clogging.

Although the coarse filter unit 35 is also provided with aself-contained bypass valve 4i, it will be understood that thislast-named bypass valve is ordinarily set for operation at .asubstantially higher pressure than the bypass valves .6? in the finefilter units .36 and 31. Since the capacity of the coarse filtering unit35 is usually greater than both fine filtering units 3.5 and 31,

the bypass valve 41 is provided primarily as a safety precaution, onlyin case of practically complete clogging of the coarse filtering unit 35long after the latter unit should properly have been replaced in thefiltering system. The necesnoted, as usual, by pressure readings in thesystem, or by visual inspection of the liquid output from the filter.

When it is desired to remove the several filtering units for inspectionor replacement, the cap This permits I5 is removed from the casing H3.bodily removal of the pressure plate 55 which holds all the filterunits, both coarse and fine, in seated engagement on the respectivenipples 25,

30 and SI, so that any or all the fiiter'units can.

wherein all of the liquid normally is passed first through the coarsefiltering unit and then through a plurality of fine filtering units,under conditions where the capacity of. the fine filtering units may notbe sufficient to take care of all the liquid passed through the coarsefiltering unit. Self-contained iby-pass means are provided in the finerfiltering units to insure a continuous flow of liquid through theapparatus.

It will be observed further that the liquid will be passed in seriesfrom the coarse filtering unit into the main filtering compartment 20and from thence in parallel through a plurality oi gfine filtering unitsto the outlet. Nevertheless; allithe filtering units, both coarse andfine, are: de-

tachably retained by single retaining mean's so that they can be readilyremoved for replacement or repair. 1

Although I have shown and described a prac tical and operative device,obviously other changes could be made in my invention by those skilledin the art to which invention pertains and,

relation to the inlet of said casing, and the} fine filtering units eachhaving a centrally disposed tubular member opening at one end thereofdirectly connected in detachable relation with the outlet of saidcasing, so that all the incoming liquid will normally pass through thecoarse filter and then pass in divided paths through the fine filterunits, each of said filter units being" detachable and removable fromsaid casing ,independently of the other units, and the tubular membersof each of said fine filter units including self-contained bypass meansfor bypassing liquid under predetermined pressure from said coarsefilter unit to the outlet. I

2. A filter in accordance with claim 1, wherein the casing has atransverse partition at the bottom thereof, and communication with theinlet and outlet of said casing is through a plurality of nipplesmounted on said partition and the tubular members of said coarse andfine filter units respectively, having seating connection at their lowerends with their respective and means are provided in said casing.

tachably engaging the opposite ends of said filter .L 6 I units, andholding the ends of said tubularmni bars in seated relation with theirrespective nipples. 12' i1 3. A filter'in accordance with claim 1,wherein the casing h'afsa transverse partition at the bottom thereof,and communication-with the inlet and outlet of said casing is throug'ija plurality of nipples lmounted on said partition and the coarse andhue filter units each include tubular center nienib'ers surrounded byfiltering material, said tubular members adapted to have seatingconnection at their lower ends with their respective nipples, saidtubular members having positioning members at their upper ends, and aspring-pressdpressure plate in the upper end of said casifi havinginterfitting engagement 1 iids of said positioning members of saidfilterin units for detachably holding said filter units insaid casingwith the lower ends of their tubular in embers in seated relation withtheir respectivenipples.

4. In a filter? in accordance with claim 3, wherein thecasing has aremovable cover plate at its upper end separate from said pressure platewith spring means interposed between said cover and said pressure platewhen the cover is secured to the casing.

. CORLISS D. NUGENT.

IBEFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

